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Abstract-In this paper, we investigate load balancing problem in 3GPP Long Term Evolution (LTE) network. Since LTE network aims to serve heterogeneous users with different Quality of Service (QoS) requirements, the influence of load imbalance is quite different. For those users with minimum rate requirements, it may result in high block probability, while for others without minimum rate requirements, the throughput of boundary users may be degraded. In this paper, we take all the differences into account and formulate the problem as a multi-objective optimization problem. Then we analyze its complexity, and propose our solution framework, which includes QoS-guaranteed hybrid scheduling, QoS-aware handover for users with and without QoS requirements, and call admission control. Extensive simulations are conducted and the results show that the proposed framework leads to significantly better load balancing, and thus the decrease in call block probability of users with QoS requirements, and the increase in throughput of boundary best effort users.Index Terms-3GPP LTE, load balancing, Quality of Service (QoS)

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Accumulating studies have evaluated the association of Alpha-2-Macroglobulin gene (A2M) 5 bp insertion/deletion (5 bp I/D, rs3832852) and Ile1000Val (rs669) polymorphisms with Alzheimer's disease (AD) risk, but the results remain inconclusive. To investigate whether these two polymorphisms facilitate the susceptibility to AD, we conducted a comprehensive systematic review and meta-analysis. Databases of PubMed, Embase, Web of Science, Medline, CNKI, and Google Scholar were searched to get the genetic association studies. All statistical analyses were conducted with Review Manager 5.2 and STATA11.0. Fifty-two articles were included in the final meta-analysis. We performed meta-analysis of 39 studies involving 8,267 cases and 7,932 controls for the 5 bp I/D polymorphism and 27 studies involving 6,585 cases and 6,637 controls for the Ile/Val polymorphism. Overall results did not show significant association between these two polymorphisms and AD risk in dominant, recessive, and multiplicative genetic models. On the stratification analyses by ethnicity and APOE ε4 status with genotypes of polymorphism sites, similar negative associations were found. The meta-analysis suggests that there is no enough evidence for associations of A2M gene polymorphisms (5 bp I/D, Ile1000Val) with AD risk at present, even after stratification by ethnicity and APOE ε4 with genotypes of polymorphism sites. However, due to the heterogeneity in the meta-analysis, the results should be interpreted with caution.

A thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Master of Engineering in Network Engineering. Victoria University of Wellington 2012I am most grateful to my supervisor Professor Winston Seah, who has helped me throughout the course of my Masters degree. He has guided me towards a realistic and interesting research topic, provided support and valuable suggestions. Winston has impressed faculty and students alike, both as an advisor and researcher. He has taught me how to improve my research skills, how to identify/address a problem and, how to write technical journals. We have learnt a lot from him during our numerous discussions.Wei Li is a senior lecturer in the school. He has given valuable suggestions and shared his experiences in the research field as one friend would to another.Mike Lin and Dong Xia, my lab mates, for extending helping hands throughout the course of my study. They helped me understand the fundamentals and improved my coding skills. They worked along with me when I encountered programming bugs. Casimirraj Subramanian, for proof reading my thesis which improved iii iv the thesis quality.Information and Communication Networks Laboratory of Niigata University release the OLSRv2 module for QualNet that includes the ETX metric. It has been very useful from the beginning of my simulation. I would also like to thank IMAI Hiroei from the Information and Communication Networks Laboratory. We corresponded through emails, and each contact helped me understand the OLSRv2 module a little better.Ross Whitcher of VillageNets for providing the network topology maps which were useful for plotting node locations in our simulations.I want to thank everyone in the Network Engineering Research Group for making it a stimulating place to work and learn. My lab mates deserve special thanks for being patient with my questions.